The first version of nation-wide open 3D soil database for Sri Lanka

Abstract

Soil data for Sri Lanka are available through semi-detailed series maps that were developed based on limited soil profile data combined with expert knowledge. This data plays a vital role in decisions at national and regional levels. However, the present format of this database does not allow for their wider use in crop simulation modelling and other related agricultural research that require finer scale data. This is due to the fact that cross-country profile data are not harmonised based on standard depths. Several attempts were made to produce digital soil data for Sri Lanka at different geographic scales, however, a completely harmonised data that covers variability across depths and properties is yet to be made available. In this article, we describe the first version of the open digital soil database that was developed using a database of 122 locations across the country. Soil properties were harmonised for standard depths using equal-area quadratic smoothing splines. Out of several interpolation methods that were evaluated for univariate interpolation, maps which were produced with the least overall error (RMSE) in the process of cross-validation were selected. The newly developed digital soil database contains 9 soil properties; pH, bulk density, cation exchange capacity, organic carbon, volumetric moisture content at 0.33 and 15 bars levels, sand silt and clay content. Moreover, the data are available for five standard depth layers as 0–5, 5–15, 15–30, 30–60 and 60–100 cm in raster format at 1 km spatial resolution. Both interpolated property maps and their error maps were stored in an open repository and made available for public use. The first version of all maps is also showcased online through open web mapping services. The repository will be gradually updated with higher resolution and more accurate maps as more samples become available and better interpolation method are used. This data could provide complementary information for insight generation at finer scales where limited local informaiton about soils hinders agricultural development.

Niche dynamics of Memecylon in Sri Lanka: Distribution patterns, climate change effects, and conservation priorities

“…However, incomplete information on occurrence data and identification errors of a large number of Memecylon specimens from the other South Asian regions impeded constructing niche models and understanding ancestral niches. Sri Lanka has a rich diversity of soils distributed across the island (Wimalasiri et al, 2020 ); however, information about the soil requirements of Memecylon is totally lacking. Therefore, future studies should also include soil data to understand the abiotic niches of Memecylon .…”

Agronomic Biofortification of Zinc in Rice for Diminishing Malnutrition in South Asia

“…Additionally, a digital soil map of Nepal was recently developed and released by the Nepal Agricultural Research Council, and it provides fruitful site-specific nutrient recommendations for agricultural crops in Nepal [126,127]. Likewise, studies are being conducted to generate digital soil maps in Bangladesh [128] and Sri Lanka [129].…”